What are the advantages and disadvantages of HVDC power supp

Advantages of high voltage DC power supply
1.DC transmission line only positive and negative wire, simple structure, low loss, low cost.
2.DC cable transmission capacity, low cost, difficult to aging, long service life.

100kw DC load bank
3.Dc power transmission does not have the stability problem of AC power transmission and meets the requirements of long-distance large-capacity transmission.
4.dc transmission of active power and reactive power consumption can be controlled by the control system, in order to improve the operation ability of the AC system.
5.HVDC can be easily built and expanded in stages.
6. Both the active power sent and the reactive power consumed by THE DC transmission can be controlled manually or automatically, which is more conducive to the economic operation and modern management of the power grid.
Two, the disadvantages of high voltage DC power supply
1. Compared with AC substation, DC power supply has more equipment, complex structure, high cost, large loss, high operation cost and poor reliability.
2. For the AC side, in addition to serving as a load or power supply, it is also a harmonic current source.
3. Thyristor converters need to consume a lot of reactive power when changing current. Reactive power compensation equipment shall be installed at each converter station.
Some technical problems caused by the use of ground (or sea water) as THE DC transmission line, because the DC circuit breaker does not have zero crossing current, it is difficult to solve the arc extinguishing problem, bringing difficulties to production.